SSH tunnel problem -- buffering data...

From: Brian Genisio (briangenisio_at_yahoo.com)
Date: 05/01/03

  • Next message: Rahul Kalaskar: "Re: SSH tunnel problem -- buffering data..." 
    Date: Thu, 1 May 2003 08:08:08 -0700 (PDT)
To: secureshell@securityfocus.com

    Hi all...

    I am using SSH to tunnel (Using LocalForwarding ports) from one application to
    another. The system exists of a controller software in Linux (where the SSH
    server resides), and the actual software in Cygwin.

    Cygwin connects to the Linux SSH server and sets up a port forward. The Linux
    app sends a small amount of data (about 12 bytes) 30 times per second.

    The problem is that the Cygwin/SSH side of the tunnel is buffering the data
    before it sends it to the Cygwin app. The result is the data is received in
    bursts, and the control is not fluid.

    I have tried this system in a Linux to Linux situation, and the buffering did
    not happen. Also, I have tried sending data from Cygwin to Linux, and the
    buffering does not happen. It only happens when data is being sent from Linux
    to Cygwin.

    I have also tried switching between LocalForward and RemoteForward, and it is
    the dirction that matters, not the type of port forwarding.

    Both sides sets the TCP_NODELAY flag before it starts sending, and I know the
    SSH code does the same...

    I should also add that none of this is noticed if SSH is taken out of the loop.

    Any ideas?
    Brian

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  • Next message: Rahul Kalaskar: "Re: SSH tunnel problem -- buffering data..."

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